Electrical connector



Jan. 21 1941. c. E. GILBERT 2,229,288

ELECTRICAL CONNECTOR I Filed Feb. 16, 1938 v INVENTOR. CHARLES E.GILBERT vim ATTORNEY.

Patented Jan. 21, 1941 s PATENT OFFICE f ELECTRICAL CONNECTOR Charles E..Gilbert, New York, N. Y.

Application February 16,

1938, Serial No. 190,683

3 Claims. I (01. 1735361) This invention relates to a new and useful improvement in electrical connectors, such as are used for making electrical connection between an electrical outlet and appliance or between two electric cords, and numerous other uses which will occur to those skilled in the art.

Among the objects of the invention is the prov vision of a connector having a minimum of parts, which can be produced at a minimum of cost, in which the contact elements are securely retained and held in correct alinement, and also'in contact with a conductor without the use of screws, rivets or other attaching devices, in which the connection of the cord to the contact elements is a step in the assembly of the connector itself and in which the possibility of short circuiting is eliminated. 1

The form of the invention shown in the drawing and described herein is commonly called an electric plug and will be so referred to herein, but it will be understood that the invention is not limited thereto, but is applicable to various other types of connectors.

In the drawing:

Figure 1 is a front elevation of an electric plug embodying the invention assembled and connected to a cord having'two conductors;

Figlure 2 is a plan view of the plug shown in F Figure 3 is .an enlarged longitudinal section taken as indicated by the lines 3-4 and the corresponding arrows in Fig. 2;

Figure 4 is also an enlarged longitudinal sec,- tion .taken as indicated by the lines 4-4 and the corresponding arrows in Figs. 2 and Figure 5 is a view of one side of a contact element; I

Figure 6 is an edge view of the same contact element; and

Figure 7 is .a view of the side of thecontact element opposite to that of Figure 5.

As shown in the drawin the connector consists of but three parts-the body i and two contact elements 2 and 3. The body may be molded in a single piece and by a single operation from Bakelite, or other suitable insulating material. Each contact element may be made by a'sing le stamping operation from a single strip of conducting material bent upon itself as at 4 to form a two-legged prong adapted for insertion into an electrical outlet. One leg 5 of the contact element is somewhat longer than the other leg 6. Adjacent the free end of leg 5 an outwardly and upwardly projecting tongue I is provided which may be produced by stamping, so that an Figure 3, the body disappear at or the leg directly behind the tongue issecured. The other leg 6 is preferably provided with an outwardly bowed and downwardly extending tongue 8, also preferably obtained by stamping. 1

In, body I there is provided for each contact element a recess 9, the general shape of which is shown in Figures 2 and 3. Also as shown in l is provided with an opening I0 through which the end of the electric cord 10 can be passed, this opening l0 connecting at its upper-end with the lower end of each recess 8. Recesses 9 are separated by the central portion H of the plug body i, which, as shown in Fi ure 3, tapers gradually from its upper end to-.

aperture in wards the bottom. \Adiacent its upper end central portion H curves outwardly to 01m substantial shoulders l2 projecting into each recess 9. The lower end of portion ll beginning at point i2a, somewhat above the bottom of recesses 9, consists oi an arch-like structure as shown in Figures 3 and 4, forming two sharp ribs, extending downwardly along opposite sides of opening I0 and gradually decreasing in height until they slightly above the lower end of opening I0 as best shown in Fig. 3..

Opposed sides of each recess 9 are each provided with a channel H, the depth of which is such that the over-all width oi recess Q, including these channels, is'very slightly greater than 3 the width of the contact element, as most clearly shown in Figures 2 and 4. The width oi. each channel M is slightly greater than the thickness of the two legs 5 and 6 of the contact element, as will be seen from Figure 3. Channel ll extends from the upper end of the body to a point l5 somewhat above the bottom of recess a. The

bottom of recess 9 is provided with an upwardlyextending rib [8 preferably slightly oilset inwardly from the bottom of channel H. The space be- 40 tween the bOttOmOf channel l4 and the top of rib Ii should preferably be somewhat less than the diameter of the electrical conductor lncluding its rubber insulation.

Assembly of the contact elements and the plug body is performed in conjunction with connects ing the cord so that a complete assembly of the plug and cord is effected by a single operation, thereby saving labor, time and cost. To perform this assembly the cord is split to separate the two conductors therein, and the insulation removed from the end of the conductors. The cord is then-passed upwardly through opening ll. The arch-like structure, with its tapering ribs ii of gradually increasing height, will cause the two conductors separate and to 'pass one into each recess 9 through which they are guided by body portion ll, until they project therefrom.

The bare end i! of each conductor is then The insulated pontion' of the conductor immediately adjacent the'portion which has been bared will be forced tact element into the bot-tom of recess 9, as shown at 8, and will be severely pinched between the lower end of leg 5 of thecontact element and rib It in the bottom of recess 9.. From this point it curves sharply over rib i6 into the upper end of opening i0. Thus a sharp double :bencl is given to the insulated conductor and it is also as above explained, so that it 30 is impossible to pull the conductor out of the contact element, and the bare end ll of the conductor is relieved of all strain. 7

When the, contact element is inserted in recess as'will be seen from Figure 3, projects inwardly towards the central portion ,ll of the body, will snap under shoulder ii of central portion II and may beforced still-more definitely int-o engage- -ment therewith by means of a suitable tool, 40 through the channel l9, provided for the purpose. In this way the contact element is se-, curely locked within the recess. and cannot be unintentionally displaced or removed. Tongue '1 also serves as a brace for the lower 45 end of leg 5 of the contact element, materially strengthening it, helping to maintain it in correct alinement and assisting it to pinch the conductor between it and rib l8.

Considerable dimculty has been experienced 50 by the short circuiting of the conductors within electric plugs, due to the carelessness of the asof the central opening l they 55 make contact with each other. In the plug of this invention this cannot occur because the archlike structure extending substantially throughout the length of opening III formed by the two ribs l3, p the two conductors apart, so that 60 in' order to cause a short circuit it sary to strip the ends of bothwires for a much greater distance than even the most careless workman would be guilty of. Thus, rib I3 serves two purposes, both of which are exceedingly im- I by the lower end of the conwill be necesthe lower end of the,

ti-on H of the body so that it is absolutely impossible for short ,clrcuiting .to occur between them, and the ,body is greatly strengthened through the substitution of this solid, integral part for the usual thin walls which are inevitable when the central opening extends entirely through the body, as has been the common practice.

Tongues 8 on contact elements 5 and 6 may be omitted, but they are advisable. It is a very common experience to find that the blades of the contact elements are very insecurely held by the contacts of [the electrical outlet. The spring tension of the contacts of the outlet are supposed .to press against the contact blades of the plug with adequate tension, but very frequently they are-too weak or have been .bent through use, so that they fail to hold the plug securely or to make positive electrical connection. This has resulted not only in much annoyance, but has even caused fires as the result of arcing. Tongues 8 obviate this annoyance and danger; they are positioned in themid section of each contact element so that they will enter the outlet when the connector is inserted and will either press against the walls of .the recesses of the outlet in which the blades are received to hold the plug securely within the outlet irrespective of the pressure between the blades and contacts, or they will engage resiliently with the contacts of the outlet ensuring firm holding and good contact, depending upon how the outlet is constructed.

The aperture formed by the stamping out of tongue 1 in leg 5 may also be found useful in the case of a conductor having unusually heavy insulation, to provide a space into which the end of the insulation can project so that the bend in the bare wire at the lower end of shorter leg 6 will not be so abrupt as to endanger its strength, and so that the pressure upon the lower end of leg 5 will not be so great as to make it difiicult to bring the two legs together sufliciently toenable them to enter channels I4.

I claim:

1. An electrical connector consisting of a unitary body of insulating material, a centrally positioned passage extending into said body from end and communicating with said passage, said recesses being symmetrically positioned on either side of the longitudinal axis of said passage and separated by an inwardly-tapering portion of said body whereby and to pass one into each recess, the inner end of each recess also being separated from the inner end of said passage by a rib, a contact conducting material bent upon itself to form a two-legged blade, one. end of which is seated in said recess and when so seated is adapted to make contact with an electrical conductor and to force it against the bottom of said recess so that it will be bent sharply around the end of said contact element and bent again in the opposite direction over said rib, said contact element also being provided with an outwardly proinsulating material, a

so I

sitioned passage extending into said body from I wardly-tapering portion of said body whereby the two conductors of an electric cord introduced into the'said passage may be caused to separate and to pass one into each recess; theinner end of each recess also being separated from the inner end of said passage by a rib, a contact element for each recess consisting of a strip of conducting material bent upon itself to form a two-legged blade, one end of which is seated in "said recess and when so seated is adapted to make contact with an electrical conductor and to force it against the bottom of said recess so that it will be bent sharply around the end of said contact element and bent again in the opposite direction over said rib, and said body having a shoulder constricting each recess adjacent its outer end and said contact element being provided with an ofiset tongue engaging with said shoulder to securely lock said contact in said recess when seated as aforesaid.

3. An electrical connector which includes a rigid unitary body of insulating material provided with a passage extendinginwardly from one end, the opposite sides of said passage being provided with longitudinal ribs of progressively increasing height, a plurality of recesses extending into said body from the other end, the lower ends of which open laterally into the inner end of said passage, said recesses being separated bylan inwardly-tapering portion of said body which 'joins the inner ends of said, ribs, said ribs'and said tapering portions of said body comprising means whereby the individual conductors of an electrical cord introduced into said passage are caused to separate and to pass into different recesses, a contact element for each recess adapted for connection to one of said conductors and consisting of a strip of conducting material bent upon itself to form a twolegged blade, the free ends of which are seated in the recess so as to pinch and securely hold the bare end of a conductor positioned thereupon, one of said legs being provided with a pro- .jecting tongue engaging with said tapered portion of said body to securely lock saidcontact element in said recess.

CHARLES E. GILBERT. 

